Australian tourist comes to the rescue after people caught in rip at Christchurch's Sumner Beach

An Australian tourist has been made an unlikely hero after saving the life of one of three people caught in a rip while swimming at a Christchurch beach.

Dion Depace, 22, was in Christchurch on holiday from Melbourne when he spotted a man yelling for help at Sumner Beach shortly after 1pm today.

Mr Depace says a second person was caught in the rip further out and appeared unconscious.

The alarm was raised just before 1.30pm that swimmers were being swept out to sea on the Scarborough side of Cave Rock.

All three were transported to Christchurch Hospital in a serious condition following the incident.

The friends of two men taken to hospital say one was saved by a surfer, while a group of teenagers saved the other, Fairfax reports.

St John responded to the call with an ambulance and the Westpac Rescue helicopter although the helicopter was not needed with the rescue affected by a lifeboat and jet ski.

The Westpac Helicopter transported two people to hospital in a serious condition with another following in an ambulance by road.

Overlooking Sumner Beach, Christchurch.
Overlooking Sumner Beach, Christchurch. Source: